1. Field of the Invention
The present invention relates to a heat resistant resin composition having N-phenylmaleimide component and a production thereof.
2. Description of the Prior Art
It has been well known that a copolymer of styrene-maleic anhydride (referring to as SMA resin) has high miscibility to a copolymer of styrene-acrylonitrile (referring to as AS resin) and has high thermal deformation temperature to result in high heat resistance. Therefore, a composition having high heat resistance and high solvent resistance is obtained by blending SMA resin to AS resin. However, the composition has inferior stability at high temperature to cause a foaming, a weight loss and a crosslinkage at higher than 230.degree. C. Thus, it has been difficult to mold the composition by a conventional injection molding process.
In order to improve the stability of SMA resin or the composition thereof at high temperature, it has been studied to incorporate a conventional antioxidant such as a phenol type, amine type or phosphorus type antioxidant into the SMA resin or the composition thereof, however a desired effect has not been found.